Effect of cooling regimes on compressive strength of concrete with lightweight aggregate exposed to high temperature

2013 ◽  
Vol 41 ◽  
pp. 21-25 ◽  
Author(s):  
Mehmet Burhan Karakoç
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Lightweight Aggregate ◽  
Compressive Strength Of Concrete

scholarly journals Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
K. O. Oriola
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Materials ◽  
Palm Kernel ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Lightweight Aggregate Concrete ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

scholarly journals Thermal and mechanical properties of PCM-incorporated normal and lightweight concretes containing silica fume

2019 ◽  
Vol 46 (7) ◽  
pp. 643-656 ◽  
Author(s):  
Amin Moshtaghi Jafarabad ◽  
Morteza Madhkhan ◽  
Naser P. Sharifi
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Thermal Performance ◽  
Phase Change Materials ◽  
Mechanical Characteristics ◽  
Lightweight Aggregate ◽  
Salt Hydrate ◽  
Promising Strategy ◽  
Compressive Strength Of Concrete ◽  
Physical And Mechanical Characteristics

Improving the thermal performance of concrete, as an important construction and pavement material, by incorporating phase change materials (PCMs) has been the topic of much research. Also, various carrier agents such as lightweight aggregate (LWA) have been introduced to incorporate PCMs into concrete. However, incorporation of PCM-impregnated LWA reduces the compressive strength of concrete. In this study, the application of silica fume to improve the compressive strength of PCM-incorporated concrete is investigated. Two types of PCMs, salt hydrate PCM and polyethylene glycol PCM, were incorporated into concrete via scoria LWA, and different physical and mechanical characteristics of the concrete were studied when silica fume was incorporated into the mix. The results show that incorporation of silica fume increases the compressive strength of PCM-incorporated concrete, and at the same time does not diminish the thermal performance of the incorporated PCM. Therefore, incorporation of silica fume was found to be a promising strategy to improve the compressive strength of PCM-incorporated concrete.

scholarly journals Experimental Research on High Temperature Resistance of Modified Lightweight Concrete after Exposure to Elevated Temperatures

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ke-cheng He ◽  
Rong-xin Guo ◽  
Qian-min Ma ◽  
Feng Yan ◽  
Zhi-wei Lin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Modification Method ◽  
Superior Mechanical Properties ◽  
Axial Compressive Strength ◽  
Crushed Limestone

In order to improve the spalling resistance of lightweight aggregate concrete at high temperature, two types of modified materials were used to modify clay ceramsite lightweight aggregates by adopting the surface coating modification method. Spalling of the concrete specimens manufactured by using the modified aggregates was observed during a temperature elevation. Mass loss and residual axial compressive strength of the modified concrete specimens after exposure to elevated temperatures were also tested. Concrete specimens consisting of ordinary clay ceramsites and crushed limestone were manufactured as references for comparison. The results showed that the ordinary lightweight concrete specimens and the crushed limestone concrete specimens were completely spalled after exposure to target temperatures above 400°C and 1000°C, respectively, whereas the modified concrete specimens remained intact at 1200°C, at which approximately 25% to 38% of the residual compressive strength was retained. The results indicated that the modified lightweight concrete specimens have exhibited superior mechanical properties and resistance to thermal spalling after exposure to elevated temperatures.

Experimental investigation on the compressive strength of PFGP-covered concretes exposed to high temperature

2019 ◽  
Vol 10 (4) ◽  
pp. 399-410
Author(s):  
Amir Hamzeh Keykha
Keyword(s):  
Experimental Investigation ◽  
Compressive Strength ◽  
High Temperature ◽  
Design Methodology ◽  
Polypropylene Fiber ◽  
Content Type ◽  
Gypsum Plaster ◽  
Compressive Strength Of Concrete

Purpose This study aims to investigate the effect of high temperature (600°C) on the compressive strength of concrete covered with a mixture of polypropylene fiber and gypsum plaster (PFGP). Design/methodology/approach To study the compressive strength of concrete specimens exposed to temperature, 16 cubic specimens (size: 150 mm × 150 mm × 150 mm) were made. After 28 days of processing and gaining the required strength of specimens, first, polypropylene fiber was mixed with gypsum plaster (CaSO4.2H2O) and then the concrete specimens were covered with this mixture. To cover the concrete specimens with the PFGP, the used PFGP thickness was 15 mm or 25 mm. The polypropylene rates mixed with the gypsum plaster were 1, 3 and 5 per cent. A total of 14 specimens, 12 of which were covered with PFGP, were exposed to high temperature in two target times of 90 and 180 min. Findings The results show that the PFGP as covering materials can improve the compressive strength lost because of the heating of the concrete specimens. The results also show that the presence of polypropylene fiber in gypsum plaster has the effect on the compressive strength lost because of the heating of the PFGP-covered concrete. The cover of PFGP having 3 per cent polypropylene fiber had the best effect on remained strength of the specimens. Originality/value The cover of PFGP having 3 per cent polypropylene fiber has the best effect on remained strength of the PFGP covered specimens exposed to temperature.

scholarly journals Supervised Learning Methods for Modeling Concrete Compressive Strength Prediction at High Temperature

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1983
Author(s):  
Mahmood Ahmad ◽  
Ji-Lei Hu ◽  
Feezan Ahmad ◽  
Xiao-Wei Tang ◽  
Maaz Amjad ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Supervised Learning ◽  
Mean Squared Error ◽  
Cement Content ◽  
Coefficient Of Determination ◽  
Percentage Error ◽  
Learning Methods ◽  
Inference System ◽  
Compressive Strength Of Concrete

Supervised learning algorithms are a recent trend for the prediction of mechanical properties of concrete. This paper presents AdaBoost, random forest (RF), and decision tree (DT) models for predicting the compressive strength of concrete at high temperature, based on the experimental data of 207 tests. The cement content, water, fine and coarse aggregates, silica fume, nano silica, fly ash, super plasticizer, and temperature were used as inputs for the models’ development. The performance of the AdaBoost, RF, and DT models are assessed using statistical indices, including the coefficient of determination (R2), root mean squared error-observations standard deviation ratio (RSR), mean absolute percentage error, and relative root mean square error. The applications of the above-mentioned approach for predicting the compressive strength of concrete at high temperature are compared with each other, and also to the artificial neural network and adaptive neuro-fuzzy inference system models described in the literature, to demonstrate the suitability of using the supervised learning methods for modeling to predict the compressive strength at high temperature. The results indicated a strong correlation between experimental and predicted values, with R2 above 0.9 and RSR lower than 0.5 during the learning and testing phases for the AdaBoost model. Moreover, the cement content in the mix was revealed as the most sensitive parameter by sensitivity analysis.

Development of Lightweight Aggregate Concrete Containing Pulverized Fly Ash and Bottom Ash

2008 ◽  
Vol 400-402 ◽  
pp. 379-384 ◽  
Author(s):  
Theradej Litsomboon ◽  
Pichai Nimityongskul ◽  
Naveed Anwar
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Apparent Density ◽  
Abrasion Resistance ◽  
Bottom Ash ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Lightweight Materials ◽  
Aggregate Concrete ◽  
Compressive Strength Of Concrete

This study examines the feasibility of using different lightweight aggregates (LA) and bottom ash as coarse and fine aggregates in concrete with fly ash. The lightweight materials were composed of 3 types, namely pumice, cellular lightweight aggregate and MTEC lightweight aggregate. The tests for physical and mechanical properties of lightweight aggregate concretes (LWAC) were conducted in terms of workability, compressive strength, apparent density, abrasion resistance and absorption. Test results showed that compressive strength of LWAC increased with an increase in apparent density, which is mainly depending on the type of aggregate. The replacement of normal weight sand with bottom ash resulted in a decrease both in density of concrete by 180-225 kg/m3 and 28-day compressive strength of concrete by 16-26%. Moreover, the use of bottom ash to replace sand in concrete increased the demand for mixing water due to its porosity and shape and to further obtain the required workability. The type and absorption of LA influenced predominantly the water absorption of LWAC. Total replacement of natural sand by bottom ash increased the absorption of the concrete by 63-90%. With regard to abrasion resistance, the abrasion resistance of lightweight aggregate concrete was mainly dependent on the compressive strength of concrete: the higher the strength, the higher the abrasion resistance of LWAC. In addition, the use of bottom ash as a fine aggregate resulted in a lower abrasion resistance of lightweight aggregate concrete due to its porosity. Of the three types of lightweight materials, MTEC LA had achieved both low density and high compressive strength.

scholarly journals A Reciprocal Research on Compressive Strength of Conventional Concrete and Carbon Fibre Concrete Exposed to High Temperature

2019 ◽  
Vol 8 (12) ◽  
pp. 5767-5772
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Concrete Structure ◽  
Conventional Concrete ◽  
Fibre Concrete ◽  
Overall Performance ◽  
Compressive Strength Of Concrete ◽  
Concrete Elements

An look up has been function to evaluated the have an impact on of evaluated temperature on the compressive strength of grade concrete M25, the goal of the discover out about used to be once to actuate and observe the big difference in compressive strength containing no fiber and concrete with fiber as properly as have an impact on of temperature on compressive strength of concrete. 72 concrete cubes of 150mm measurement have been cast. The carbon fibers used in the learn about are 6mm long chopped carbon fibers& dosage of 0.3%, 0.6%, and 0.9% by the weight of concrete. Concrete elements exposed to fire, undergo bodily changes or spalling which leads to expose metal reinforcement .This motives misery in concrete structure .The overall performance of the concrete can be lengthen with the addition of carbon fiber. Undergo bodily changes or spalling which leads to expose metal reinforcement .This motives misery in concrete structure .The overall performance of the concrete can be lengthen with the addition of carbon fiber. It can be noticed that carbon fiber reinforcement exhibits more compressive strength than the conventional concrete exposed to high temperature.

scholarly journals PENGARUH JENIS AGREGAT RINGAN BUATAN TERHADAP KUAT TEKAN BETON RINGAN = EFFECT OF ARTIFICIAL LIGHTWEIGHT AGGREGATE TYPE FOR COMPRESSIVE STRENGTH OF LIGHTWEIGHT CONCRETE

2019 ◽  
Vol 13 (1) ◽  
pp. 27
Author(s):  
Nurul Aini Sulistyowati ◽  
Deden Suripto
Keyword(s):  
Compressive Strength ◽  
Specific Gravity ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Lightweight Concrete ◽  
Raw Materials ◽  
Lightweight Aggregate ◽  
Mechanical And Physical Properties ◽  
Husk Rice ◽  
Compressive Strength Of Concrete

The aim of the research was to know the mechanical and physical properties of lightweight aggregate and compressive strength of concrete with lightweight aggregate. The raw materials for manufacturing lightweight aggregate include the mix composition of shale + sawdust, shale + rice husk, shale + rice husk ash, and shale. Th structural lightweight concrete was designed to have a compressive strength of 25 MPa. The specimen was cylindrical of 10 diameter and 20 cm high. The compressive strength of concrete tested at ages of 14 days, 21 days, and 28 days. Specific gravity of lightweight aggregate was less than 1.5, the best water absorption was of the lightweight aggregate shale and the best hardness that of the lightweight aggregate shale+ rice husk ash. The compressive strength of concrete with lightweight aggregate shale + sawdust 265.04 kg/cm2 and shale + rice husk ash 264.73 kg/cm2, all of which were higher than compressive strength. The compressive strength of concrete with lightweight aggregate shale + rice was husk 234.82 kg/cm2 and that of the shale was 212.23 kg/cm2 , which were lower than the designed compressive strength.Keywords : artificial lightweight aggregate, lightweight concrete, shale, sawdust, rice husk, rice husk ash AbstrakPenelitian bertujuan untuk mengetahui sifat fisis dan mekanis agregat ringan serta kuat tekan beton yang menggunakan agregat ringan. Pembuatan agregat ringan menggunakan komposisi campuran shale + serbuk gergaji kayu, shale + abu sekam padi, shale + sekam padi, serta shale. Pembuatan beton ringan struktural menggunakan rancangan campuran dengan kuat tekan rencana sebesar 25 MPa. Benda uji berbentuk silinder dengan diameter 10 cm dan tinggi 20 cm. Pengujian kuat tekan beton dilakukan pada umur 14 hari, 21hari dan 28 hari. Berat jenis agregat ringan kurang dari 1,5 dengan penyerapan air terbaik pada agregat ringan shale dan kekerasan terbaik pada agregat ringan shale + abu sekam padi. Kuat tekan beton agregat ringan shale + serbuk gergaji sebesar 265,04 kg/cm2 dan agregat ringan shale + abu sekam padi 264,73 kg/cm2 lebih tinggi dari kuat tekan rencana. Kuat tekan beton agregat ringan shale + sekam padi sebesar 234,82 kg/cm2 dan agregat ringan shale sebesar 212,23 kg/cm2 lebih rendah dari kuat tekan rencana.Kata kunci : agregat ringan buatan,beton ringan, shale, serbuk gergaji kayu, sekam padi, abu sekam padi

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